U.S. patent application number 11/103699 was filed with the patent office on 2005-10-20 for hand-held spectrometer.
Invention is credited to Beecroft, Michael Thomas, Ferguson, James Paul, Matsumoto, John Fujima, Smith, Barry James, Szczesniak, Marian Martin.
Application Number | 20050229698 11/103699 |
Document ID | / |
Family ID | 35094891 |
Filed Date | 2005-10-20 |
United States Patent
Application |
20050229698 |
Kind Code |
A1 |
Beecroft, Michael Thomas ;
et al. |
October 20, 2005 |
Hand-held spectrometer
Abstract
A hand-held portable modular spectrometer unit. The unit
includes a detachable head containing a light source and optical
components for detecting spectral information from light reflected
from or transmitted through a target and a processor for converting
the detected spectral information into digital information. The
unit also includes a plug-in rechargeable power supply and a
control module for controlling the components in the measurement
head. The controller includes a computer processor for analyzing
the digital information produced by the measurement head and a
display monitor for displaying spectral information produced by the
control unit. In preferred embodiments the plug-in rechargeable
power supply is a 12-volt off-the-shelf power-tool rechargeable
battery unit. In preferred embodiments several measuring heads are
available. These include a gas cell measuring head, a surface
reflectance measuring head that includes and integrating sphere, a
specular reflectance measuring head, a grazing angle measuring
head, an attenuated total reflectance measuring head, a diffuse
reflection measuring head, a non-volatile residues measuring head,
a liquid transmission cell measuring head and a fluorescence
measuring head. Each of these measurement heads includes a
spectrometer. Several types of spectrometers are available
including those based on filters, prisms, gratings and
interferometers. The unit can operate in a wide range of
wavelengths including the infrared, visible and ultraviolet
spectral ranges.
Inventors: |
Beecroft, Michael Thomas;
(Temecula, CA) ; Szczesniak, Marian Martin;
(Temecula, CA) ; Smith, Barry James; (Oceanside,
CA) ; Matsumoto, John Fujima; (Encinitas, CA)
; Ferguson, James Paul; (Menifee, CA) |
Correspondence
Address: |
JOHN R. ROSS
PO BOX 2138
DEL MAR
CA
92014
US
|
Family ID: |
35094891 |
Appl. No.: |
11/103699 |
Filed: |
April 11, 2005 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
60561410 |
Apr 12, 2004 |
|
|
|
Current U.S.
Class: |
73/300 |
Current CPC
Class: |
G01J 3/0208 20130101;
G01J 3/0264 20130101; G01N 2201/0221 20130101; G01J 3/0235
20130101; G01J 3/0254 20130101; G01N 21/33 20130101; G01N 2201/065
20130101; G01N 21/552 20130101; G01N 21/3504 20130101; G01J 3/02
20130101; G01J 3/0291 20130101; G01J 3/42 20130101; G01J 3/0283
20130101; G01N 21/31 20130101; G01N 21/645 20130101; G01N 2021/3595
20130101; G01J 3/0272 20130101 |
Class at
Publication: |
073/300 |
International
Class: |
G01F 023/00 |
Goverment Interests
[0002] This invention was in the course of a SBIR Contract No.
N41756-02-M-1045 with the United States Navy and the United States
government has rights in the invention.
Claims
What is claimed is:
1. A hand-held portable modular spectrometer system comprising: A)
at least one detachable head comprising 1) a light source and
optical components including a spectrometer for detecting spectral
information from light reflected from or transmitted through a
target and 2) a processor for converting the detected spectral
information into digital information, and B) a control module
configured as a hand-held module comprising: 1) a plug-in
rechargeable power supply and 2) a control unit for controlling the
components in the measurement head, said control unit comprising:
a) a computer processor for analyzing the digital information
produced by the measurement head and b) a display monitor for
displaying spectral information produced by the control unit.
2. The system as in claim 1 wherein the plug-in rechargeable power
supply is a 12-volt off-the-shelf power-tool rechargeable battery
unit.
3. The system as in claim 1 wherein said control unit comprises
computer and display components of off-the-shelf personal digital
assistants.
4. The system as in claim 3 wherein said control unit is programmed
with Microsoft Windows CE software.
5. The system as in claim 1 and further comprising a plurality of
additional detachable measurement heads.
6. The system as in claim 5 and further comprising detachment means
for removing said head and breaking electrical connections in a
single operation and for replacing said head with another head and
making electrical connections in a single operation.
7. The system as in claim 6 wherein said detachment means comprises
a threaded collar.
8. The system as in claim 5 wherein each measurement head is
configured to operate with a laptop, tablet, or desktop computer
via a USB computer interface and a small AC power supply or battery
power supply.
9. The system as in claim 5 wherein each measurement head contains
an embedded microprocessor which provides all the processing
capability and the USB computer interface needed to run the
measurement head.
10. The system as claim 5 wherein each measurement head comprises a
microprocessor.
11. The system as in claim 5 wherein said head is configured for
use in situations when extensive measurements are to be made in an
industrial or laboratory environment, when portability is not
needed or when a higher computer power than is available in the
control module is needed.
12. The system as in claim 11 wherein said head is controlled from
an external PDA, PC, notebook, or a custom made computer.
13. The system as in claim 5 wherein each of said heads comprises a
functioning spectrometer operable with no external computing power
providing information that can be communicated with manufacturing
networks.
14. The system as in claim 5 wherein each of said heads is
configured so that it could be placed on a robotic arms for
unattended unsupervised inspections.
15. The system as in claim 5 wherein each of said heads is
configured to be capable of running a range of self diagnostics
aimed at determining the current performance of the measurement
head and comparing it to its factory settings.
16. The system as in claim 5 wherein each of said measurement head
are configured to warn the user when the unit is not working within
specifications.
17. The system as in claim 5 wherein each of said measurement heads
is factory calibrated before sale.
18. The system as in claim 5 wherein each of said measurement heads
preferably calibrated using a Fourier transform infrared (FTIR)
spectrometer for the task of determining actual measured spectra of
the system as a whole.
19. The system as in claim 5 wherein each of said measurement heads
tested and certified for operation at specific design wavelengths
by injecting light into the optical train of the measurement head
with a FTIR spectrometer, with light from the spectrometer starting
at the light source location inside the measurement head and
traversing optics within the head until it reaches the detector
where an interferogram is measured.
20. The system as in claim 5 wherein at least one of said
measurement heads is configured to make spectral measurements in
the infrared spectral range.
21. The system as in claim 5 wherein at least one of said
measurement heads is configured to make spectral measurements in
the visible spectral range.
22. The system as in claim 5 wherein at least one of said
measurement heads is configured to make spectral measurements in
the ultra-violet spectral range.
23. The system as in claim 5 wherein at least one of said
measurement heads is configured to make spectral measurements in
the x-ray spectral range.
24. The system as in claim wherein optical components of at least
one of said measurement heads is suspended on a flexible mount.
25. The system as in claim 1 wherein said system is configured to
have power tool like ergonomics.
26. The system as in claim 1 wherein said at least one detachable
measurement head is a gas cell measuring head.
27. The system as in claim 1 wherein said at least one detachable
measurement head is a surface reflectance measuring head.
28. The system as in claim 1 wherein said at least one detachable
measurement head is a a surface reflectance measuring head that
includes and integrating sphere.
29. The system as in claim 1 wherein said at least one detachable
measurement head is a specular reflectance measuring head.
30. The system as in claim 1 wherein said at least one detachable
measurement head is a grazing angle measuring head.
31. The system as in claim 1 wherein said at least one detachable
measurement head is an attenuated total reflectance measuring
head.
32. The system as in claim 1 wherein said at least one detachable
measurement head is a diffuse reflection measuring head.
33. The system as in claim 1 wherein said at least one detachable
measurement head is a non-volatile residues measuring head.
34. The system as in claim 1 wherein said at least one detachable
measurement head is a directional hemisphere reflectance measuring
head.
35. The system as in claim 1 wherein said at least one detachable
measurement head is a liquid transmission cell measuring head.
36. The system as in claim 1 wherein said at least one detachable
measurement head is a fluorescence measuring head
37. The system as in claim 1 wherein said spectrometer is a
filter-based spectrometer.
38. The system as in claim 1 wherein said spectrometer is a
prisms-based spectrometer.
39. The system as in claim 1 wherein said spectrometer is a
gratings-based spectrometer.
40. The system as in claim 1 wherein said spectrometer is an
interferometer-based spectrometer.
41. The system as in claim 1 wherein said spectrometer is a
filter-based spectrometer.
Description
[0001] The present invention relates to spectrometers and in
particular to portable spectrometers. This application claims the
benefit of U.S. Provisional Application Ser. No. 60/561,410 filed
Apr. 12, 2004.
BACKGROUND OF THE INVENTION
[0003] Applicants' employer, Surface Optics Corporation, developed
during the 1990's a series of small rugged portable spectrometers.
Some of these units have been successfully marketed as model
SOC400. These units were powered by a 12 volt power supply, such as
a car battery and required the addition of an associated computer,
such as a desk-top or lap-top computer, to operate. The units
included optical components for producing illumination at a variety
of controlled spectra. These components include systems utilizing
broad band light sources and optical filters to produce
illumination at several specific wavelengths. Interferometers were
used to produce illumination at a series of wavelengths. These
devices are very useful for measuring diffuse reflectance of a
target or sample. The spectra of the reflectance can identify
target material. These units have been engineered into modular
systems in which various "heads" could be interchanged allowing a
single unit to be used for a variety of purposes. These heads
included (1) an attenuated total reflectance (ATR) head, (2) a
specular 50 degree reflectance head, (3) a grazing angle 75 degree
specular reflectance head, (4) a gas cell head, (5) an integrating
sphere head. With some of the devices only a single spectral point
is measured and in other devices several spectra data is measured.
Features of these prior art devices are described in the following
patents, all of which are incorporated herein by reference:
[0004] U.S. Pat. Nos. 5,424,543, 5,821,535 and 5,949,074 describing
imaging spectrometer units and U.S. Pat. Nos. 5,714,578 and
6,147,350 describing rugged portable units with Fourier transform
infrared spectrometer illumination for diffuse reflectance spectral
measurement.
[0005] The SOC 400 has been a very successful product; however, the
unit requires a separate power source and a computer as support
equipment and in many applications a rolling cart to transport it.
These components are depicted in FIG. 1 in the '758 patent. The
measuring apparatus is depicted at 22 and the support equipment is
depicted at 24. The support equipment includes a battery and a
table-top computer 34 that controls the measuring apparatus,
receives data there from, and stores the data, analyses the data,
reports and/or displays the data.
[0006] What is needed in an even easier to use more compact modular
portable spectrometer.
SUMMARY OF THE INVENTION
[0007] The present invention provides a hand-held portable modular
spectrometer unit. The unit includes a detachable head containing a
light source and optical components for detecting spectral
information from light reflected from or transmitted through a
target and a processor for converting the detected spectral
information into digital information. The unit also includes a
plug-in rechargeable power supply and a control module for
controlling the components in the measurement head. The controller
includes a computer processor for analyzing the digital information
produced by the measurement head and a display monitor for
displaying spectral information produced by the control unit. In
preferred embodiments the plug-in rechargeable power supply is a
12-volt off-the-shelf power-tool rechargeable battery unit. In
preferred embodiments several measuring heads are available. These
include a gas cell measuring head, a surface reflectance measuring
head that includes and integrating sphere, a specular reflectance
measuring head, a grazing angle measuring head, an attenuated total
reflectance measuring head, a diffuse reflection measuring head, a
non-volatile residues measuring head, a liquid transmission cell
measuring head and a fluorescence measuring head. Each of these
measurement heads includes a spectrometer. Several types of
spectrometers are available including those based on filters,
prisms, gratings and interferometers. The unit can operate in a
wide range of wavelengths including the infrared, visible and
ultraviolet spectral ranges.
[0008] Important features of the invention include:
[0009] Utilization of cordless power drill basic shape for a
scientific instrument.
[0010] Utilization of power tool off shelf battery as power source
for a scientific instrument, in particular for a hand held
spectroscopic monitor.
[0011] Modularity of the scientific hand held instrument allowing
for interchangeability of measurement heads attached to a command
module to accommodate variety of spectroscopic measurement
techniques within the same tool. This concept:
[0012] lowers the manufacturing cost,
[0013] lowers the cost to the user,
[0014] presents a user with a suite of tools for field hand held
analysis.
[0015] Ability of the measurement heads to function independently
from the command module being replaced by a power and communication
adapter.
[0016] A concept of a suite of scientific tools based on the same
command module, with similar in look and operation replacement
measurement heads for achieving variety of spectroscopic analysis
in a portable hand held operation.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] FIG. 1 is a front view of the SOC410 Handheld
Reflectometer
[0018] FIG. 2 is a rear view of the SOC410 Handheld
Reflectometer
[0019] FIG. 3 is a front section view of the Command Module
[0020] FIG. 4 is a rear section view of the Command Module
[0021] FIG. 5 is a rear view ATR measurement Head
[0022] FIG. 6 is an exploded view ATR measurement head
[0023] FIG. 7 is an ATR measurement head optical layout
[0024] FIG. 8 is a specular 50 degree measurement head optical
layout
[0025] FIG. 9 is a grazing angle measurement head optical
layout
[0026] FIG. 10 is a cell measurement head
[0027] FIG. 11 is a butane gas calibration curve
[0028] FIG. 12 is an ethylene gas calibration curve
[0029] FIG. 13 is a directional Hemispherical Reflectance
measurement head section view
[0030] FIG. 14 is a directional Hemispherical Reflectance
Integrating Sphere
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
SOC410 Handheld Reflectometer
[0031] FIG. 1 shows important features of a preferred embodiment of
the present invention. It is now a standard product of Surface
Optics Corporation. It is the SOC410 handheld reflectometer has
several key features that are common to many handheld power tools.
These include an easily replaceable rechargeable battery 6, an
ergonomically designed handle 5, and a trigger 4 to start a
measurement. The SOC410 is designed to have replaceable measurement
heads 1 which are attached to the handle with a threaded collar 2.
All the measured data is stored on a compact flash card 3 located
at the top of the unit. The SOC410 is comprised of two modular
pieces, the measurement head 1, 2 and the command module 3, 4, 5,
6. The measurement head contains all the necessary hardware to
perform its intended function with the exception of a computer and
power which is supplied by the command module.
[0032] FIG. 2 shows a rear view of the SOC410 handheld
reflectometer is operated using a QVGA (320 pixel.times.240 pixel
LCD panel touch screen interface 7 and the trigger 6. The touch
screen interface allows the user to select different modes of
operation as dictated by the measurement head installed on the unit
thru the use of software buttons displayed on the touch screen
interface. When held in hand, a wrist lanyard device attaches to
the handle 8 and secures the unit from accidental drops.
[0033] The SOC410 is designed to be held with a single hand. The
measurement head is held up against the surface to be tested and
the trigger is pulled to produce a measurement of the surface to be
measured in the case of reflectometer heads. Depending on the type
of head and spectral ranges measured, different surface analysis
can be produced by each head. Other heads are designed to sample
gases of liquids in which case they are not placed against a
surface.
Command Module
[0034] The command module provides all the power and computer
processing needed to operate a measurement head. It is designed to
operate a variety of easily interchangeable measurement heads. It
is packaged into a user friendly format which is very similar to
the common battery operated power drill. This includes a pistol
grip with trigger and a battery which inserts into the bottom of
the handle. A computer is located in the handle and a touch screen
display which faces the user during operation. The user controls
the unit by selecting various software functions from the touch
screen interface and pressing trigger when a measurement is to be
made. Measurement heads are attached to the front of the command
module using a threaded collar design which is rotated to secure
the measurement head to the command module. Two electrical
connections are made when attaching the measurement head. They
provide power and data communications between the command module
and measurement head.
[0035] It is important to note that the command module has the
familiar shape of a cordless power drill and is easily carried in
one hand leaving the other hand free to operate the computer via
the touch screen interface. This cordless power drill form factor
was intentional and its purpose is to provide a functional paradigm
(how to use the instrument) that most people are familiar with and
that is: insert battery for power, hold the unit using the
ergonomic hand grip, and press the trigger when operating the
unit.
[0036] Referring to FIG. 3 and FIG. 4, details of the command
module is shown. FIG. 3 is a front isometric section that reveals
the internal workings. FIG. 4 similar to FIG. 3 except the view is
from the rear of the command module and a portion of the computer
& display assembly is shown in a section view. The primary
structure is composed of two plastic shells 9 that are nearly
mirror images of each other and, together, form a clam shell that
holds all the internal sub-assemblies in place. Those
sub-assemblies include computer 19 & display 22 which are
located in a rubber armored housing 10, power supply 26 with
interface connectors 14, 15 and integral threaded mating cylinder
17, trigger sub-assembly 12, and battery clip 13 sub-assembly. To
support the various sub-assemblies, the plastic housing provides
several other important functions which include a ergonomically
design hand grip with a conveniently placed trigger 12 which can be
used in the right or left hand. An interface for the battery
complete with locking side tabs to lock the battery into place when
inserting. A spring loaded catch 24 on the battery locks into these
tabs located on either side of the handle. A thru hole 25 at the
lower rear of the handle is used to attach a wrist strap to help
secure the command module when in use (similar to a camera
strap).
[0037] When the battery is completely inserted into the bottom of
the handle, two nickel plated terminals in the battery clip
assembly 13 make contact with the +/-terminals of the 12 V 2.6Ah
Makita series #1234 battery. The 12-Volt DC power is routed up the
Power Supply Printed Circuit Board (PCB) 26 via a wiring harness
and plugs into the power input connector 20.
[0038] The Power Supply PCB 26 generates the several voltages
needed to operate the measurement head and computer from the raw
12V supplied by the battery. Those generated voltages include +5VDC
& -5VDC analog supply voltages for the measurement head and
separate 5VDC & 3VDC digital supply voltages for the
measurement head. A high density DB9 style connector 14 located on
the front face of the command module is used to provide these
voltages to the measurement head when it is attached. This
connector also supplies the raw 12V battery voltage to the
measurement head for future use if and when needed. This raw 12V
voltage will protect the command module interface from obsolescence
since future measurement heads will be able to generate their own
voltages that were not originally planned for and thus are not
provided here.
[0039] The Power Supply PCB 19 is mounted into a brass threaded
ring 17 which the measurement head screws onto. On the front face
of the command module are three alignment holes 16 that are used to
guide the measurement head into place interchanging measurement
heads. These alignment holes accept three alignment pins on the
measurement head and prevent the electrical connector pins from
being bent by improper alignment of the mating connectors when
attaching a new measurement head.
[0040] In addition to the power supplied to the measurement head
thru the power connector 14, the Power Supply PCB also provides
several other functions. It provides three computer serial
communication protocols which are USB 2.0, I2C, and RS232. The
computer uses the RS232 to communicate with the measurement head by
sending commands to control the measurement head and receiving data
collected by the measurement head for processing. The USB 2.0
serial interface is provided thru connector 21 on the inside of the
Power Supply PCB and is used by other embodiments of this invention
to provide direct computer control using a standard desktop or
laptop computer to operate the measurement heads without the need
or the command module. The USB 2.0 is also available to talk with
the embedded computer in future embodiments of this invention. A
I2C communication link is used to talk with individual integrated
circuits on all the PCB's. All communications between the command
module and the measurement head are made thru the D-Sub Mixed
Layout connector 15 when a measurement head is attached. The
trigger is attached to this board which allows the computer to
sense when the trigger is pulled. The trigger sub-assembly 12 is
comprised of a trigger which slides on two spring loaded rails.
When the trigger is depressed it closes a momentary style switch
which is wired into the Power Supply PCB.
[0041] The Power Supply PCB 26 also supplies 7.5V power the
computer and RS232 thru two connectors mounted on the rear of the
PCB. The power and communications are wired into an industrial PDA
(personal data assistant) style embedded computer 19 (Inhand
Electronics model number Fingertip3). The computer runs Windows
CE.net 4.1 operating system. A video display adaptor PCB is used by
the computer to operate the Liquid Crystal Display (LCD) 22 (Sharp
Electronics #LQ35Q7 DB02). This LCD comprises a QVGA screen which
means that is has a resolution of 320.times.240 pixels or a quarter
of a standard VGA screen. The screen is has a backlight which can
be turned on or off to improve contrast and/or save battery life.
It also has an integral touch screen interface which can be
operated using a touch screen stylus or by applying pressure with a
finger. This entire computer sub-assembly is protected with a
rubber bumper guard 10 that surrounds the perimeter of the
sub-assembly.
[0042] The user operates the unit by pressing soft buttons (buttons
in the software) that are displayed on the LCD for the user. The
LCD display also displays all the relevant data when a measurement
is made. This data and the software are stored on a Compact Flash
(CF) card 18 which is inserted into the top of the unit. This card
can be removed and inserted in a laptop or desktop computer when
data needs to be transferred to a PC. A Secure Digital (SD) card
slot on the computer is also provided for future growth when
needed. The use of the CF card allows vast amounts of data to be
stored for later retrievable. CF cards are now commercially
available that can hold as much as 1 gigabyte of data.
[0043] The user software provides the user interface for operating
the SOC410. This software contains a variety of menus and buttons
that allow the user to navigate thru the software to setup
measurements, to run extensive diagnostics to test the integrity of
the measurements, and to process the raw data once it has been
measured.
[0044] During a measurement sequence the user is provided feedback
by one of three different mechanisms, the touch panel display 22, a
super bright LED 23, and a vibration motor 11 in the handle which
is designed to vibrate the handle. Often during a measurement it is
difficult to view the screen during the measurement sequence which
may last several seconds during which time the user must hold the
unit still. These three methods of feedback guarantee that the user
will get the required feedback indicating the completion of
measurement regardless of the user/SOC410 orientation.
Attenuated Total Reflectance Measurement Head
[0045] A first preferred measurement head is the Attenuated Total
Reflectance (ATR) measurement head. Referring to FIG. 5, a rear
view of the ATR measurement head is shown. This rear view is
typical of all the measurement heads in that it has several
features that all measurement heads have in common. A thread collar
31 is used to secure the measurement to the command module. Three
alignment pins 28 accurately align the measurement when attaching
to the command module such that both interface connectors 29, 30
are properly orientated. An aluminum cover 27 protects all the
internal mechanisms for the environment.
[0046] FIG. 6 is an exploded view of the ATR measurement head
showing the three major assemblies that comprise the head. These
are the electronics module 32, the optical assembly 34, and the
aluminum cover 35. The front face of the measure head 33 is pressed
against the sample during a measurement. Again, as stated earlier,
all the measurement heads share these three assemblies in different
forms. In fact, the electronics module 32 is common to all the
different embodiments of the measurement heads describe herein.
[0047] Two separate electronic printed circuit boards (PCB's)
located in the electronics module 32 provide much of the electrical
related functionality for the measurement head. One PCB is a
digital communication board which handles three communication
protocols: RS232, USB 2.0, and I2C. This board comprises a
microprocessor that provides intelligence for the head. It controls
an analog to digital converter, detector gain levels, chopper
motors, a bandpass filter wheel, pivoting mirrors, source power,
detector power and cooling, detector temperature monitor,
measurement head temperature monitor, and monitors power supply
voltage levels. This is achieved using direct digit IO lines and
the I2C interface. This board also comprises mating portions of
power supply connector 29 and digital communications connector 30
that mate to the power supply board inside the command module.
[0048] The second major PCB is analog board that provides DC motor
circuitry for up to three motors. In this embodiment the motors are
used to control an optical chopper shown in FIG. 7 at 37 and 34 and
bandpass filter wheel 39. This board also provides circuitry for
biasing the detector and thermo-electrically cooling the detector.
Many detectors do not require biasing or thermoelectric cooling in
which case this circuitry would sit idle. Also in other heads
different motors are utilized but the same electronics module can
be used interchangeably.
[0049] Optical Assembly
[0050] The optical assembly is the assembly that defines the type
of data each measurement head is used to collect. It is where are
the work is done. Whereas each measurement head has the same
electronics module and functionally equivalent covers, the optical
assembly is always different in both form and function. The optical
systems can all be reduced to 5 components and they are:
[0051] 1) the source 43,
[0052] 2) optical chopper 37,
[0053] 3) the sampling optics which in this case is the ATR crystal
36,
[0054] 4) the spectrometer which in this case is bandpass filter
39, and
[0055] 5) a detector 40.
[0056] FIG. 7 shows the optical assembly with just the important
optical components exposed. The optical train for the ATR
measurement head begins at the source 43. The source in the ATR
embodiment is an electrically heated incandescent Kanthal filament
source sealed in an inert argon environment behind an IR
transmissive window of ZnSe. This source is manufactured to
specification by Carley Lamps. The source power is computer
controlled via the electronics module 32 and can be varied from 0
to 6 volts depending on the requirements of the measurement head
and measurement to be performed.
[0057] The source is focused thru a miniature optical chopper 37
that modulates the light for better signal to noise performance.
The voltage to the chopper motor 44 is also controlled via the
electronics module 32 and can be varied to change the speed of the
motor. This changes the frequency that the light is modulated. The
modulated light bounces thru the Diamond ATR crystal 36 supplied by
Pike Technologies (U.S. Pat. No. 5,965,889). The modulated light
strikes a diamond face 42 in the crystal where it is totally
internally reflected when exposed to air. When pressed against a
sample some of the light is absorbed to varying degrees depending
of the wavelength and the sample that the diamond face 42 is
pressed against. In this embodiment the ATR crystal are the
sampling optics which are used to probe the physical nature of the
sample.
[0058] After bouncing thru the ATR crystal 36 (requiring at least
five discrete bounces), the light is directed thru the
spectrometer, a bandpass filter wheel 39 via a fold mirror 38. The
computer controlled bandpass filter wheel 39 can be rotated into
one of fourteen different positions 41. At different positions a
different bandpass filter would be mounted which would measure a
different spectral band. After the light passes thru a particular
bandpass filter in the bandpass filter wheel it is measured by the
detector. In this case a DTGS pyroelectric detector is used and it
is provided by British Aerospace Engineering part number P5121.
Each measurement head embodiment is capable of using different
detectors depending of the requirements of the measurement head.
The detector senses the modulated light which is then converted
into a digital signal and sent to the electronics module for
processing. The electronics module demodulates the signal and
passes that on to the computer in the command module for final
processing over either the RS232 line or the USB 2.0 line.
[0059] The remaining measurement head embodiments describe here are
all very similar to the ATR measurement head. They all have the
same electronics module, a functionally equivalent cover, and an
optical assembly. The optical assemblies of all the measurement
heads all share five basic components, a source, an optical
chopper, sampling optics (in this case an ATR crystal), a
spectrometer (in this case bandpass filter wheel), and a detector
(in this case a. DTGS pyroelectric detector).
Specular 50 Degree Angle Reflectance Measurement Head
[0060] The specular 50 degree reflectance measurement head
embodiment is nearly identical to the ATR measurement head
embodiment. The only difference is the sampling optics which
determines how the sample is probed. In this case the sample's
specular reflectance is measured at an angle of 50 degrees. As
such, only the optical assembly is discussed here since all other
details are identical to the previous embodiment.
[0061] Referring to FIG. 8, the optical layout of the specular 50
degree measurement head is shown. Again the optical layout starts
with the source 51 which focuses the light thru an optical chopper
52 and into the sampling optics portion of the measurement head.
Here the sampling optics are designed to illuminate the sample at
50 degree angle with respect to the normal of the sample. The light
reflected into the 50 degree specular direction is then captured
and directed into the spectrometer portion of the measurement head.
This is accomplished with four different mirrors. The first fold
mirror 53 redirects the modulated light from the source toward an
elliptical mirror 45. This mirror focuses the beam onto the sample
46 which is represented schematically by an elliptical outline
whose boundary illustrates the size of the beam on the sample. A
faceplate at the front of the instrument precisely locates the
sample at this focal point 46 when the measurement head is pressed
up against the sample.
[0062] Typically, light is reflected off the sample in all
directions. The elliptical mirror 47 only collects the light in the
specular direction and funnels it thru a fold mirror 48 and into
the spectrometer. In this case the spectrometer is the bandpass
filter wheel 49. After the light passes thru the spectrometer, it
is measured by a DTGS detector 50.
[0063] Although similar to the ATR measurement head, the specular
50 degree measurement head measures a different optical property
entirely. Depending on the sample, one method or the other may be
best for characterizing the surface to be measured.
Grazing Angle Reflectance Measurement Head
[0064] The grazing angle reflectance measurement head embodiment is
nearly identical to both the ATR measurement head and the specular
50 degree angle reflectance measurement head embodiment. The only
difference, again, is the sampling optics which determines how the
sample is probed. In this case the sample's grazing angle
reflectance is measured at an angle of 75 degrees. As such, only
the optical assembly is discussed here since all other details are
identical to the previous embodiments.
[0065] Referring to FIG. 9, the optical layout of the grazing angle
measurement head is shown from a different perspective than shown
in the case of the specular 50 degree angle reflectance measurement
head. Again the optical layout starts with the source 60 which
focuses the light thru an optical chopper 61 and into the sampling
optics portion of the measurement head. Here the sampling optics
are designed to illuminate the sample at a grazing angle of
incidence with respect to the normal of the sample. The light
reflected into grazing specular direction is then captured and
directed into the spectrometer portion of the measurement head.
This is accomplished with four different mirrors. The first fold
mirror 63 redirects the modulated light from the source toward an
elliptical mirror 62. This mirror focuses the beam onto the sample
54 which is represented schematically by an elliptical outline
whose boundary illustrates the size of the beam on the sample. In
this case the beam is a very eccentric ellipse because of the high
angle of incidence the source beam. A faceplate at the front of the
instrument precisely locates the sample at this focal point 54 when
the measurement head is pressed up against the sample.
[0066] Typically, light is reflected off the sample in all
directions. The elliptically mirror 55 only collects the light in
the specular direction and funnels it thru a fold mirror 56 and
into the spectrometer. This case the spectrometer is our bandpass
filter wheel 58. The light from the fold mirror 56 strikes another
fold mirror which sends the light into the spectrometer. After the
light passes thru the spectrometer, it is measured by a DTGS
detector 59.
[0067] Although similar to the ATR measurement and the specular 50
degree measurement head, the grazing angle measurement head
measures a different optical property than either of these other
two. Depending on the sample, one method or the other may be best
for characterizing the surface to be measured.
Gas Cell Measurement Head
[0068] Infrared spectroscopy has been used from its beginning for
analysis of matter in gas phase. By analysis is meant understanding
of spectroscopic properties of gases. Once those were understood
for a specific gas, this knowledge has been used to identify that
gas, to detect its presence, and to quantitatively predict that gas
concentration. Technical methods have been developed for all of
those analyses. The device and method described here is a novel
device and a novel method for gas analysis. Its main characteristic
is its portability and modularity, its shape and way in which it
can be utilized. There are many portable gas phase analyzers,
especially utilized for detection of specific gases. However, all
of them are packaged in form of boxes. All sorts of box shaped gas
analyzers are available on the market. Some of them are miniature,
some larger, some are equipped with wands for gas "sniffing". But
they all are box like shaped. What we are proposing is a device
which is shaped like a household power tool and to be used as a
tool. In addition, the proposed gas analyzer constituted by the
Command module and the Gas Head can be quickly modified into
another gas (from methane to ammonia) analyzer just by replacing
the measurement head on the Command Module. Further the Gas
Analyzer can be quickly modified into a surface or powder analyzer
just by changing the analytical head on the Command Module. Other
aspects of this innovation are described elsewhere in the patent
document.
[0069] The gas cell embodiment of this invention is shown in FIG.
10. This is a modular hand-held gas cell spectrometer. It sucks gas
from an environment into a cell and measures transmission of light
through the sample at a variety of wavelengths to produce an
absorption or transmission spectrum for the gas. The unit consists
of a command module and a measurement head. Here is gas cell
measurement head is shown attached to the command module which is
illustrated in a section view and which was described in an earlier
embodiment.
[0070] This measuring head is one of several measuring heads that
can be utilized with this invention. This measuring head turns the
present invention into a "gas sniffer" for monitoring gasses. Gas
from an environment is sucked into gas cell 66 by gas pump 69
(miniature gas pump by Sensidyne) through gas inlet 68. The gas is
exhausted through outlet 65. The head includes a light source 72
which in this preferred embodiment is a broad band infrared source
custom built by Carley Lamps Inc. The emitting beam is focused at
the aperture 74 after passing through a beam chopper 73. The
spherical mirror 64 (Edmund Scientific Inc.) focuses the beam at
the focal point of the White cell. A flat mirror directs the beam
to the focal point of the gas cell. The beam travels thru the gas
cell 66 in multiple passes. Each pass increases the optical path of
the beam thru the gas cell which in turn increases the sensitivity
of the device. The beam exiting the cell is refocused by a
spherical mirror 67 thru a discrete narrow bandpass filter wheel 70
(the spectrometer) to the infrared light detector 71. In this
embodiment a 10 cm base pass White gas cell 66 by Infrared Analysis
Inc. is used. The total length of the optical pass is 2.5 m. Some
of the beam intensity is lost due to multiple reflections and some
of the energy is absorbed by the present gas. In preferred
embodiments with the gas cell evacuated, about 90 percent of the
beam passing through aperture 74 exits to filter wheel 70 and the
portion passing the filters are detected in detector 71. The filter
wheel comprises up to 8 filters each designed to pass only a narrow
band of wavelengths. These filters are available from suppliers
such as OCLI, or Barr Associates. The filter wheel is software
controlled and each filter is spun into position and a measurement
at the detector is made at the wavelength. Depending of the
specific gas to be measured, several filters may be rotated into
position to measure specific absorption bands to identify the gas
and/or gas concentration. The filters are supplied by OCLI. The
filter wheel is moved by a motor (MicroMo model number
1016M012GK380+10-1/16) controlled from the processor on the Digital
Board. The output of detector 71 (by Cal Sensors BXT2S Series PbSe
Detector) is initially amplified by the preamplifier board on which
it is mounted. The signal is further processed by the Analog Board,
and then by the Digital Board. From there the signal is sent over
RS232 protocol and over the connector on the Digital board and the
connector the Power Supply board to the PDA computer in the Command
Module. In this impediment the gas Cell head is used to quantify
presence of a know gas.
[0071] To perform a measurement the gas cell is filled with a
spectrally neutral gas like nitrogen or dry air. The baseline
signal is recorded I.sub.b. Next, the cell is filled with gas
mixture to be analyzed and a sample reading is recorded I.sub.s.
The ratio of the I.sub.s over I.sub.b indicates the quantitative
amount of the analyzed gas. Surface Optics Corporation designed
software operating on the PDA computer allows for instrument
calibration and quantitative data predictions. A calibration curve
is developed with gas mixtures of known analytical gas
concentration present. That calibration curve is used for
predictions of concentrations of analyzed gases.
[0072] FIGS. 11A and B and 12A and B show the calibration curves
for two different types of gases, butane and ethylene respectively.
Was the calibration curve is established, the signal at the
detector is linearly proportional to the gas being measured.
Directional Hemispherical Reflectance Measurement Head
[0073] FIG. 13 shows the Directional Hemispherical Reflectance
(DHR) measurement head which contains all the optics and
electronics needed to make DHR measurements. The only parts that
are missing are a computer to display the results and a power
supply to power the unit. This measurement head is designed to
measure total hemispherical reflectance at two incident angles (20
degrees and 60 degrees) at six different wavelengths of interest.
To accomplish this an integrating sphere with specialized source
optics for illuminating the sample at two incident angles are used.
In addition, 6 different detectors are also used to measure the six
wavelengths of interest.
[0074] The DHR measurement head is comprised of three different
assemblies and they are the electronics module 76, 82, the cover
75, 77, and the optical assembly 78, 81, 80. The electronics module
is the same as that which was described earlier. In the case the
cover has a front rubber boot 77 which is designed to flex during a
measurement unlike previous covers mentioned in the previous
embodiments. The optical assembly is what separates this
measurement head from previous measurement heads. The integrating
sphere 78 is mounted at the front of the unit and is designed to
make contact with the sample at the sampling port 79 of the
integrating sphere. The view in FIG. 13 also shows the preamp for
the PbSe/PbS 4 band detector 81, and the IR source 82. The entire
optical assembly is mounted on a flexible coupling 80 that suspends
the optics in the middle of the unit. This coupling is designed to
allow the entire optical train to move and conform to the sample
surface when the sample port on the integrating sphere is pressed
against the sample.
[0075] The flexible coupling is attached to an internal bulkhead
inside the DHR measurement head. Behind this bulkhead sits two
additional electronic boards that make up the electronics module
82.
[0076] FIG. 14 illustrates the complete optical path from source to
sample to detector for the SOC410 DHR Head without the supporting
mechanical structure or electronics. As with any optical
reflectometer we must start at the source 83. A cut-away view of
the source shows the filament mounted inside a cylinder. A rear
elliptically shape reflector focuses the energy out thru a ZnSe
window. At peak temperatures, the source filament (Kanthal
filament) reaches temperatures of approximately 975 deg Celsius.
The ZnSe window seals in the inert Argon environment that prolongs
the life of the source filament. As a result, the filament is not
exposed directly to the internal atmosphere of the unit. This is an
important consideration when measuring materials in the presence of
volatile gases.
[0077] A fold mirror 84 redirects the source beam thru a optical
chopper 86 and onto an elliptical aperture 85. The optical chopper
86 is used to modulate the light to improve signal stability and
signal to noise while the elliptical aperture 85 is designed to
control the illuminated area on the sample.
[0078] The illuminated aperture is imaged onto the sample by an
elliptical mirror 87. This mirror sits just below the aperture and
redirects the incoming beam upward at a 45 degree angle onto the
pivot mirror 88. The pivot mirror directs the beam into the
integrating sphere thru the incident beam port 89 on the upper half
of the sphere. The pivot mirror is named because it pivots about
one of three positions. These positions are called the 20 degree
incident beam 92, the reference beam 91, and the 60 degree incident
beam 90. The 20 degree incident beam 92 position directly
illuminates the sample port at approximately 20 degrees. The
reference position strikes the side of the integrating sphere. The
location of the integrating sphere that the reference beam strikes
is specular so that the beam is reflected up into the upper
hemisphere. The 60 degree incident beam 90 hits a 60 degree fold
mirror 94 on the side of the integrating sphere which then
redirects the light onto the sample port at an angle of
approximately 60 degrees.
[0079] The integrating sphere sample port is pressed against the
sample to make a measurement. The pivot mirror is rotated thru its
various positions during a measurement at which point the sample is
illuminated at 20 and 60 degree incident beam. The sample is
typical removed when the reference beam is measured. All three beam
positions result in light being scattered up into the integrating
sphere.
[0080] The integrating sphere 97 interior surface is largely
composed of a sandblasted gold plated aluminum surface. The
exceptions being the ports, the 60 degree fold mirror (specular
gold coating), and the spot on the integrating sphere that the
reference beam hits (specular gold coating). In fact, all the
optical mirrors in the system are gold coated with the exception of
the source which is polished aluminum.
[0081] The light scattered into the integrating sphere bounces
around until it is absorb by the gold coating, the sample, escapes
out the incident beam port, or passes thru either of two detector
baffles. The light traveling into the detector baffle and onto the
detector is what is measured. This voltage measured at the detector
is directly proportional to the reflectance of the sample when the
sample is located at the sample port.
[0082] Two detector ports are used to allow 6 different detector
elements to view the interior of the integrating sphere. The
baffles prevent the detector from viewing the sample directly.
Three PbSe detector elements and 1 PbS detector element is housed
inside a single thermo-electrically cooled package and sees into
the integrating sphere thru one baffle 95. Each detector element
has a filter placed above it so that it only sees the band of
interest which in this case are 3-5 um, 3-4 um, 4-5 um (all PbSe)
and 1.5-2.5 um (PbS) bands. The second detector baffle 96 is used
for a DTGS (8-12 um) and Silicon diode (0.7-1.1 um) detectors.
[0083] This entire optical measurement assembly is mounted on a
flexible universal coupling 80. It is important to the integrity of
the measurement that the sample port 79 is pressed squarely up
against the sample surface. Without this flexible coupling the user
would have to the entire unit very precisely perpendicular to the
sample surface during a measurement. This is very difficult to due
if not impossible in many situations. The flexible universal
coupling allows the user to push the measurement head up against
the surface and it will compliantly align itself without requiring
the user to hold the unit very still during a measurement.
Other Measurement Heads
[0084] Diffuse Reflectance Measurement Head
[0085] Diffuse reflectance is a popular method for analysis of
powder materials and surfaces with rough finish. Surface Optics
Corporation developed a diffuse reflectance measurement head for
the SOC 400 FTIR in 1995. The Diffuse Reflectance Measurement Head
is not a typical infrared accessory. It is not an accessory at all.
Surface Optics Corporation introduced in mid 90 ties reflectance
accessories with built in light detector (reflectance and
transmission accessories for the SOC 400 FTIR. In the present
embodiment, the source of infrared energy, optics, spectrometer,
detector and most of processing electronics are in the measurement
head. In addition to illumination and detection optics, the head
comes with all the elements found in the first embodiment. It
consists the following elements: digital electronic board, analog
electronic board, source of IR radiation, chopper, illumination
optics, reflective beam collection optics, focusing optics, filter
wheel, infrared detector, other supportive electronics and a
cover.
[0086] V-Sphere Measurement Head
[0087] VSphere is Surface Optics Corporation's invention and a
unique way for detection, identification and quantification of
nonvolatile components in solvents. It is used in the aircraft,
spacecraft, industrial hygiene semiconductor, and other industries.
The users are organizations like NASA, Boeing, 3M, Intel,
Maxtor.
[0088] Liquid Transmission Cell Measurement Head
[0089] A liquid transmission cell measurement head can also be used
with the command module. It is not a typical infrared accessory. It
is not an accessory at all. Surface Optics Corporation introduced
in 1990's reflectance accessories with built in light detector
which include reflectance and transmission accessories for the SOC
400 FTIR. In this embodiment the source of infrared energy, optics,
spectrometer, detector and most of processing electronics are in
the measurement head. In addition to illumination and detection
optics, it comes with all the elements found in the first
embodiment. It consists of the following elements: digital
electronic board, analog electronic board, source of IR radiation,
chopper, illumination optics, reflective beam collection optics,
focusing optics, filter wheel, infrared detector, other supportive
electronics, and cover.
[0090] Fluorescents Measurements
[0091] The fluorescents measurements measurement head may also be
used with the command module. It is not a typical infrared
accessory. It is not an accessory at all. Surface Optics
Corporation introduced in mid 90 ties reflectance accessories with
built in light detector which include reflectance and transmission
accessories for the SOC 400 FTIR. In this embodiemnt the source of
infrared energy, optics, spectrometer, detector and most of
processing electronics consists of the Specular Reflectance
measurements head. In addition to illumination and detection
optics, it comes with all the elements found in the first
embodiment. It consists of the following elements: digital
electronic board, analog electronic board, source of IR radiation,
chopper, illumination optics, reflective beam collection optics,
focusing optics, filter wheel, infrared detector, other supportive
electronics and cover.
[0092] Visible Color Measurements
[0093] A visible color measurement head can also be used with the
command module. It also is not a typical infrared accessory. In
this embodiment the source of infrared energy, optics,
spectrometer, detector and most of processing electronics consists
of the Specular Reflectance measurements head. In addition to
illumination and detection optics, it comes with all the elements
found in the first embodiment. It consist the following elements:
digital electronic board, analog electronic board, source of IR
radiation, chopper, illumination optics, reflective beam collection
optics, focusing optics, filter wheel, infrared detector, other
supportive electronics, and cover.
[0094] While the present invention has been described above in
terms of specific embodiment, persons skilled in this art will
recognize that many changes, additions and modifications can be
made without departing from the novel concepts described above.
Spectrometers are sophisticated devices but the components in them
do not have to be. Applicants have made a better spectrometer by
taking advantage of every-day off-the-shelf components. Two
important ones are the personal digital assistants and power tool
plug-in batteries.
[0095] Personnel Digital Assistants
[0096] Prior art spectrometers are typically equipped with
specialized computer processors that are specially selected or
designed for the spectrometer application. These processors
typically require specialized software programming. An important
feature of preferred embodiments of the present invention is the
use of off-the-shelf personal digital assistants using Microsoft
Windows CE. This computer has computer power and costs less than
the more specialized embedded microcomputer systems used in the
prior art spectrometers. Software development tools for commercial
PDA's are quite sophisticated and help dramatically improve
software productivity.
[0097] Power Tool Plug-In Battery
[0098] Applicants believe they are the first to incorporate power
tool batteries into a hand held spectrometer. The result is a
lower-cost, better performing, more easily handled spectrometer.
Advantages of these batteries include high capacity (watt-hours)
quick recharge and quick and easy battery interchange. They are
small and compact. They provide a significant voltage level (12V)
and high current draw. They use environmental friendlier
technologies such as Ni-MH versus Ni-Cadmium (heavy metals) when it
comes to the disposal of depleted batteries. They are also
conveniently located at the bottom of the handle and thus provide a
natural counterweight that balances the instrument in the hand of
the user. The preferred battery is made by Makita and it is the
same battery used for many hand held drills. It provides enough
power to last for one to three hours. It lowers the spectrometer
manufacturing cost. It lowers the maintenance cost. The replacement
batteries are easily available form most of local hardware
stores.
[0099] Interchangeable Measurement Heads
[0100] An important feature of the present invention is its
interchangeable measurement heads. Prior art portable spectrometers
had interchangeable measurement heads; however, these prior art
devices required the user to remove a front cover, unhook the
electrical connection, unbolt the accessory and then reverse these
operations after placing the new head into the control unit.
Measurement heads of the present invention can be interchanged with
tow twists of the wrist. This is accomplished by integrating the
mechanical and electrical connections such that both are made in
one operation. A threaded collar on the outside of the measurement
is rotated to make both mechanical and electrical connections with
out the need for removing any covers or using any tools to remove
covers or attach accessories.
[0101] Intelligent Measuring Heads
[0102] Measurement heads of the present invention are actually
quite smart. Each is fully self-contained, just add power and
connect USB cable to a computer and they are fully operational. In
normal operation, command module 30 provides the power and the
computer interface. However, each measurement head can operate with
a laptop, tablet, or desktop computer via a USB computer interface
and a small AC power supply or battery power supply. Each
measurement head contains an embedded microprocessor which provides
all the processing capability and the USB computer interface needed
to run the measurement head. The source, optics, detector, ADC
electronics, and microprocessor are contained within the head. Such
an arrangement can be useful when extensive measurements are to be
made in an industrial or laboratory environment when portability is
not needed or when a higher computer power than is available in the
control module is needed. The measurement heads of a hand held
spectrometer function without command module. They can be
controlled from an external PDA, PC, notebook, or a custom made
computer. The heads are fully functioning spectrometers. To
function, they need an external electrical power. They can operate
with no external computing power providing information by flashing
lights, sounding signals, sending out analog or digital signals.
They can communicate with manufacturing networks. They can be
placed on robotic arms for unattended unsupervised inspections.
[0103] Diagnostic Capabilities
[0104] Precisely because each measurement head is self contained
with all the components needed to provide a fully functioning
measurement system, preferred embodiments of the present invention
are also capable of running a complete range of self diagnostics
aimed at determining the current performance of the measurement
head and comparing it to its factory settings. Power levels are
checked as well as all the mechanical and optical settings to test
for component failure and current component status including
optical alignment status. The measurement head will even be able to
tell the user when the unit is not working within specifications,
how far out of spec and what is wrong. This will allow the supplier
to provide much better customer support in the event the unit needs
service. This level of diagnostics also provides an important
quality assurance element to the measurements for the user.
Questions such as:
[0105] Is the unit operating within specifications?
[0106] Is it aligned?
[0107] Is it calibrated?
[0108] can now be answered each time the unit is used.
[0109] Wavelength Calibration and Diagnostics
[0110] Each head preferably is factory calibrated before sale.
Heads are preferably calibrated using a Fourier transform infrared
(FTIR) spectrometer for the task of determining actual measured
spectra of the system as a whole. Each measurement head should be
tested and certified for operation at specific design wavelengths
(measurement head dependent) by injecting light into the optical
train of the measurement head with the FTIR spectrometer. The light
from the spectrometer will start at the source location inside the
measurement head. The light will then traverse the entire optical
train until it reaches the detector where an interferogram will be
measured. A fast Fourier transform of this interferogram will give
very precise wavelength calibration data on each head before
shipping. This data will be store in each head in its processors
memory for retrieval when needed.
[0111] Spectral Separation of Light Components
[0112] The present invention can utilize a wide variety of
spectroscopic techniques for providing specific spectral light
components for examining whatever needs to be spectrally examined,
be it gas, liquid, paste, powder, solid object, residue or material
surface. These techniques include:
[0113] Optical Filters
[0114] Discrete Bandpass Filters
[0115] Linearly Variable Bandpass Filters
[0116] Circularly Variable Bandpass Filters
[0117] Grating Based Spectrometers
[0118] Prism Based Spectrometers
[0119] Etalon Based Spectrometers
[0120] FTIR Spectrometers
[0121] Acousto-Optical Based Spectrometers
[0122] In addition to the wide range spectroscopic methods
available for use with the present invention, the invention is not
limited to the IR spectrum but can be used in the ultra-violet,
visible, and near infrared. In fact, future improvements maybe made
to adapt the present invention to monitor X-ray spectra, or emitted
energies induced by electron, X-ray, or UV or visible beam
illumination. Also, as indicated above, the unit can be adapted for
use for various types of reflectance measurements and for and
transmission measurements through solids, gasses and liquids.
[0123] Flexible Suspension Optics
[0124] The measurement optics of hand held spectrometers in
preferred embodiments is suspended on a flexible mount to minimize
effect of hand shaking on the recorded data. It also confirms the
measurement optic to the local shape of the analyzed sample. The
current design uses a motor shaft coupling. This coupling is also
known under name of machine spring. This coupling is also known as
spring loaded universal joint. It is used on some exotic
applications like the wheel suspension of the Mars Rover. In this
case it is used to mount optical elements of a hand held
device.
[0125] Power Tool Ergonomics
[0126] The SOC410 in packaged into a power tool like ergonomics
which Appllicants believe is new to this class of instruments. It
makes for ease of use and well balanced (physically) instrument
with the battery at one end and the measurement head at the
other.
* * * * *